@aeolun/muhammara/lib/recipe/page.js

Create, read and modify PDF files and streams. A drop in replacement for hummusjs PDF library

const muhammara = require("../muhammara");

/**
 * Create a new page, specifying either actual width and height, or the name
 * of a supported page size (eg. 'letter', )
 * @name createPage
 * @function
 * @memberof Recipe
 * @param {number|string} [pageWidth_or_pageSizeName='letter'] - The page width, or name of medium size.
 * Known named medium sizes: executive, folio, legal, letter, ledger, tabloid, a0-a10, b0-b10, c0-c10, ra0-ra4, sra0-ara4
 * @param {number} [pageHeight_or_rotation] - The page height, or rotation (90) when when page size name given.
 * @param {object} [margins] - page margin definitions.
 * @param {number} [margins.left] - Left margin.
 * @param {number} [margins.right] - Right margin.
 * @param {number} [margins.top] - Top margin.
 * @param {number} [margins.bottom] - Bottom margin.
 */
exports.createPage = function createPage(pageWidth, pageHeight, margins) {
  if (!pageWidth && !pageHeight) {
    [pageWidth, pageHeight] = this.default.pageSize;
  } else if (
    pageWidth &&
    !isNaN(pageWidth) &&
    pageHeight &&
    !isNaN(pageHeight)
  ) {
    pageWidth = pageWidth || this.default.pageSize[0];
    pageHeight = pageHeight || this.default.pageSize[1];
  } else if (typeof pageWidth === "string") {
    const rotate = pageHeight;
    const pageType = pageWidth.toLowerCase().replace("-size", "");
    const pageSize = this.default.mediumSizes[pageType];

    if (pageSize) {
      [pageWidth, pageHeight] = pageSize;
    } else {
      [pageWidth, pageHeight] = this.default.pageSize;
    }

    if (rotate && !isNaN(rotate)) {
      if (rotate % 180 != 0) {
        // swap width and height
        [pageWidth, pageHeight] = [pageHeight, pageWidth];
      }
    }
  }
  // from 0
  this.metadata.pageCount += 1;
  const pageNumber = this.metadata.pageCount;
  const dimensions = [0, 0, pageWidth, pageHeight];
  const layout = pageWidth > pageHeight ? "landscape" : "portrait";
  this.metadata[pageNumber] = {
    pageNumber,
    mediaBox: dimensions,
    layout,
    rotate: 0,
    width: pageWidth,
    height: pageHeight,
  };

  const page = this.writer.createPage();
  page.mediaBox = [0, 0, pageWidth, pageHeight];

  this.page = page;
  this.pageNumber = pageNumber;
  this.pageContext = this.writer.startPageContentContext(this.page);
  this.editingPage = false;

  if (margins) {
    this.margins(margins);
  }

  this.moveTo(0, 0);
  return this;
};

/**
 * Finish a page
 * @name endPage
 * @function
 * @memberof Recipe
 */
exports.endPage = function endPage() {
  if (!this.page) {
    return this;
  }

  if (this.page.endContext) {
    this.page.endContext();
    this.page.writePage();
  } else {
    this.writer.writePage(this.page);
  }
  // this.page = null;
  // this.pageContext = null;
  // this.pageNumber = 0;

  return this;
};

/**
 * Start editing a page
 * @name editPage
 * @function
 * @memberof Recipe
 * @param {number} pageNumber - The page number to be edited.
 */
exports.editPage = function editPage(pageNumber) {
  const pdfWriter = this.writer;
  const pageIndex = pageNumber - 1;
  const pageModifier = new muhammara.PDFPageModifier(
    pdfWriter,
    pageIndex,
    true
  );
  this.page = pageModifier;
  this.pageNumber = pageNumber;
  this.pageContext = pageModifier.startContext().getContext();
  this.editingPage = true;

  this._resumePageRotation(pageNumber);

  if (this.debug) {
    const context = this.pageContext;
    const { width, height, mediaBox } = this.metadata[pageNumber];
    const startX = mediaBox[0];
    const startY = mediaBox[1];
    const textOptions = {
      font: this.writer.getFontForFile(this.fonts["helvetica-bold"]),
      size: 50,
      colorspace: "gray",
      color: 0x00,
    };
    context.writeText(
      `[${startX}, ${startY}] is HERE`,
      startX,
      startY,
      textOptions
    );
    context.writeText(
      `[${startX}, width/2] is HERE`,
      startX,
      width / 2,
      textOptions
    );
    context.writeText(
      `[${startX}, height/2] is HERE`,
      startX,
      height / 2,
      textOptions
    );
    context.writeText(
      `[width/2, ${startY}] is HERE`,
      width / 2,
      startY,
      textOptions
    );
    context.writeText(
      `[height/2, ${startY}] is HERE`,
      height / 2,
      startY,
      textOptions
    );
  }
  return this;
};

exports._resumePageRotation = function _resumePageRotation(
  pageNumber,
  context
) {
  pageNumber = pageNumber || this.pageNumber;
  const {
    // layout,
    rotate,
    width,
    height,
    mediaBox,
  } = this.metadata[pageNumber];
  context = context || this.pageContext;
  const startX = mediaBox[0];
  const startY = mediaBox[1];
  this.page.mediaBox = [startX, startY, width, height];

  switch (rotate) {
    case 90:
    case -270:
      context.cm(0, 1, -1, 0, height - startX, startY);
      break;
    case 180:
    case -180:
      context.cm(-1, 0, 0, -1, width, height);
      break;
    case 270:
    case -90:
      context.cm(0, -1, 1, 0, startX, width - startY);
      break;

    default:
  }
  return this;
};

/**
 * Get page information
 * @name pageInfo
 * @function
 * @memberof Recipe
 * @param {number} pageNumber - The page number.
 */
exports.pageInfo = function pageInfo(pageNumber) {
  const pageInfo = this.metadata[pageNumber];
  return {
    width: pageInfo.width,
    height: pageInfo.height,
    rotate: pageInfo.rotate,
    pageNumber,
  };
};

exports.pauseContext = function pauseContext() {
  if (this.page && this.page.endContext) {
    this.page.endContext();
    // this.writer.pausePageContentContext(this.pageContext);
  } else if (this.pageContext) {
    this.writer.pausePageContentContext(this.pageContext);
  }
};

exports.resumeContext = function resumeContext() {
  if (!this.isNewPDF && this.page) {
    this.pageContext = this.page.startContext().getContext();
    this._resumePageRotation();
  }
};

exports.getPageInfo = function getPageInfo() {
  const info = this.writer.getDocumentContext().getInfoDictionary();
  return info;
};

/**
 * Set/Get current page margins.
 * @name margins
 * @function
 * @memberof Recipe
 * @param {number|object} [left] - Left margin width or an object holding margin properties to be set.
 * Valid margin property names are: left, right, top, bottom.
 * @param {number} [right] - Right margin width.
 * @param {number} [top] - Top margin height.
 * @param {number} [bottom] - Bottom margin height.
 * @returns {object} When parameters are given, the value returned is the recipe handle. When no
 * parameters given, the return value is the current page margin object.
 */
exports.margins = function margins(left, right, top, bottom) {
  let marginSet = false;

  if (typeof left === "object") {
    const margins = left;
    left = margins.left;
    right = margins.right;
    top = margins.top;
    bottom = margins.bottom;
  }

  if (left !== undefined) {
    this._margin.left = left;
    marginSet = true;
  }

  if (right !== undefined) {
    this._margin.right = right;
    marginSet = true;
  }

  if (top !== undefined) {
    this._margin.top = top;
    marginSet = true;
  }

  if (bottom !== undefined) {
    this._margin.bottom = bottom;
    marginSet = true;
  }

  // When no parameters given, send back current margins.
  if (!marginSet) {
    return this._margin;
  }

  return this;
};